scholarly journals Effects of nitrous oxide on middle ear pressure

2007 ◽  
Vol 60 (9-10) ◽  
pp. 473-478
Author(s):  
Branislava Majstorovic ◽  
Radomir Radulovic ◽  
Vojko Djukic ◽  
Dragana Kastratovic ◽  
Nada Popovic ◽  
...  

Introduction. Recent literature data suggest that permanent or reversible hearing loss may occur after general anesthesia. The etiology varies, while hearing loss following middle ear surgery is attributed to exposure to nitrous oxide (N2O). The objective of our study was to measure, using tympanometry, the middle air pressure change caused by nitrous oxide during general anesthesia and to establish its emetogenic effects during the postoperative period. Material and Methods. This academic (non-commercial) prospective study included two groups of patients (a total of 58), with ASA status I, II and III. The study group (n 30) consisted of patients undergoing unilateral ear surgery. In this group, the intratympanic pressure was measured in the unoperated (healthy) ear before and during the surgery. The control group (n 28) patients underwent nose, throat or neck surgical interventions. This group underwent measurement of bilateral intratympanic pressure in healthy ears, before and during the surgery. Both groups were operated under general balanced anesthesia. Pain, nausea and antiemetics were monitored during the first 24 postoperative hours. Statistical analysis was performed using the Mann-Whitney-Wilcoxon test. Results. This perioperative study confirmed the following: highly significant (p<0.001) increase in intratympanic pressure in non-operated ears in the study group and significant (p<0.05) in controls. However, there was no statistical significance (p>0.05) between groups. Pain was more frequent in controls, and nausea in the study group, but without significant difference (p>0.05). Conclusions. Postoperative audiometry findings showed no conductive or sensorineural hearing loss after interventions. Nitrous oxide can be used in general balanced anesthesia with discontinuation 15 to 45 minutes before insertion of the tympanic membrane and completion of middle ear surgery. .

1998 ◽  
Vol 119 (1) ◽  
pp. 125-130 ◽  
Author(s):  
Juha-Pekka Vasama ◽  
Jyrki P. Mäkelä ◽  
Hans A. Ramsay

We recorded auditory-evoked magnetic responses with a whole-scalp 122-channel neuromagnetometer from seven adult patients with unilateral conductive hearing loss before and after middle ear surgery. The stimuli were 50-msec 1-kHz tone bursts, delivered to the healthy, nonoperated ear at interstimulus intervals of 1, 2, and 4 seconds. The mean preoperative pure-tone average in the affected ear was 57 dB hearing level; the mean postoperative pure-tone average was 17 dB. The 100-msec auditory-evoked response originating in the auditory cortex peaked, on average, 7 msecs earlier after than before surgery over the hemisphere contralateral to the stimulated ear and 2 msecs earlier over the ipsilateral hemisphere. The contralateral response strengths increased by 5% after surgery; ipsilateral strengths increased by 11%. The variation of the response latency and amplitude in the patients who underwent surgery was similar to that of seven control subjects. The postoperative source locations did not differ noticeably from preoperative ones. These findings suggest that temporary unilateral conductive hearing loss in adult patients modifies the function of the auditory neural pathway. (Otolaryngol Head Neck Surg 1998;119:125-30.)


1997 ◽  
Vol 100 (7) ◽  
pp. 740-746 ◽  
Author(s):  
Masafumi Sakagami ◽  
Hiroshi Ogasawara ◽  
Michiko Node ◽  
Toru Seo ◽  
Yasuo Mishiro

2020 ◽  
Vol 5 (2) ◽  
pp. 14-19
Author(s):  
Smriti Bandhu ◽  
Arunabh Mukharjee

Background: With the introduction of intentional hypotensive anesthesia in the surgical field to achieve a relatively bloodless surgical field along with the use of the operative microscope, it has revolutionized the middle ear surgery practice. Dexmedetomidine is a relatively new and potent α2 agonist prototype found efficient in rendering bloodless intra-surgical field and inducing controlled hypotension during the surgeries of the middle ear. The objective is to present prospective study was aimed at evaluating with and without dexmedetomidine infusion effect on end-tidal isoflurane concentration for lowering blood pressure by 30%, awakening time and quality of bloodless surgical field during middle ear surgical procedure. Subjects and Methods:54 patients who were to undergo middle ear surgery and had ASA I and II were randomly divided into the two groups. In Group I Dexmedetomidine was used and in Group II Normal saline. Effect of Dexmedetomidine infusion on end-tidal isoflurane concentration for lowering blood pressure by 30%, awakening time, quality of bloodless surgical field during middle ear surgical procedure, heart rate was evaluated. The data collected were statistically analyzed. Results: The mean values of the heart rate were statistically non-significant between the groups when recorded at the baseline, whereas, a statistically significant difference was seen in the values for heart rate intra-operatively. The mean values for heart rates were significantly higher for the placebo group. A significant difference in Isoflurane concentration was found with dexmedetomidine requiring a percentage of 0.6 0.4 and normal saline 1.8 0.5. Less bleeding was seen with dexmedetomidine. Conclusion:  Dexmedetomidine is a potent hypotensive agent which also reduces the requirement of Isoflurane compared  to the normal saline placebo. The use of dexmedetomidine is relatively safe and provide a relatively bloodless surgical field, hence, increasing efficacy, and improving visibility at the surgical site.


2016 ◽  
Vol 22 (3) ◽  
pp. 213 ◽  
Author(s):  
Suat Terzi ◽  
Engin Dursun ◽  
Abdulkadir Özgür ◽  
ZerrinÖzergin Coskun ◽  
ÖzlemÇelebi Erdivanli ◽  
...  

PEDIATRICS ◽  
1984 ◽  
Vol 74 (2) ◽  
pp. 236-240
Author(s):  
Richard H. Schwartz ◽  
Kenneth M. Grundfast ◽  
Bruce Feldman ◽  
Richard E. Linde ◽  
Karen L. Hermansen

Thirty-five cholesteatomas medial to intact eardrums were treated in 34 children between 1976 and 1982. Six (18%) children had never had a documented episode of otitis media. Seventeen (50%) children, in whom the lesion was diagnosed at an early stage, underwent simple excision of the cholesteatoma without the need for extensive middle ear surgery. Findings from postoperative audiograms were normal for all such children. Cholesteatoma has recurred in eight (23%) children to date. Most recurrences were diagnosed 15 months or less after surgery. Routine careful otoscopic examination is essential in order to discover cholesteatoma at an early stage and to avoid hearing loss and the need for extensive otomastoid surgery. In order to perform an accurate examination of the eardrum, a halogen-illuminated otoscope and pneumo-otoscopy should be used by the pediatrician routinely. Particular attention should be paid to the posterior-superior quadrant of the tympanic membrance where a cholesteatoma is usually located.


2006 ◽  
Vol 120 (5) ◽  
pp. 414-415 ◽  
Author(s):  
J Ahmed ◽  
P Chatrath ◽  
J Harcourt

A rare facial nerve anomaly was incidentally discovered whilst performing a tympanoplasty and ossicular reconstruction on a patient with an acquired unilateral conductive hearing loss. The nerve was seen to bifurcate and straddle a normal stapes superstructure as it ran posteriorly through the middle ear, a unique and as yet unreported combination. This case highlights the importance of vigilance regarding facial nerve anatomical variations encountered during middle-ear surgery thus avoiding inadvertent damage. The purported embryological mechanism responsible for such anomalies of the intra-tympanic facial nerve is discussed.


1986 ◽  
Vol 95 (5) ◽  
pp. 525-530 ◽  
Author(s):  
Joseph W. Hall ◽  
Eugene L. Derlacki

This study investigated whether conductive hearing loss reduces normal binaural hearing advantages and whether binaural hearing advantages are normal in patients who have had hearing thresholds improved by middle ear surgery. Binaural hearing was assessed at a test frequency of 500 Hz using the masking level difference and interaural time discrimination thresholds. Results indicated that binaural hearing is often poor in conductive lesion patients and that the reduction in binaural hearing is not always consistent with a simple attenuation of the acoustic signal. Poor binaural hearing sometimes occurs even when middle ear surgery has resulted in bilaterally normal hearing thresholds. Our preliminary results are consistent with the interpretation that auditory deprivation due to conductive hearing loss may result in poor binaural auditory processing.


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